spi.c

MSP430F149的两个USATR 在实现SPI通讯

#include  <msp430x14x.h>

void main(void)
{
  volatile unsigned int i;

  WDTCTL = WDTPW + WDTHOLD;                 // Stop watchdog
  P1OUT = 0x00;                             // P1.0 setup for LED output
  P1DIR |= 0x03;
  P5SEL |= 0x0E;                            // P5.1,2,3 SPI option select
  P5OUT &= ~0x01;
  P5DIR |= 0x01;                            //Reset Slave
  P5DIR &= ~0x01;
  U1CTL = CHAR + SYNC + MM + SWRST;         // 8-bit, SPI, Master
  U1TCTL = CKPL + SSEL1 + STC;              // Polarity, SMCLK, 3-wire
  U1BR0 = 0x02;                             // SPICLK = SMCLK/2
  U1BR1 = 0x00;
  U1MCTL = 0x00;
  ME2 |= USPIE1;                            // Module enable
  U1CTL &= ~SWRST;                          // SPI enable
  IE2 |= URXIE1 + UTXIE1;                   // RX and TX interrupt enable

  for (i = 0xFFF; i > 0; i--);              // Time for slave to ready
  _BIS_SR(LPM0_bits + GIE);                 // Enter LPM0 w/ interrupt
}

#pragma vector=USART1RX_VECTOR
__interrupt void SPI1_rx (void)
{
  P1OUT = RXBUF1;                           // RXBUF1 to TXBUF1
}

#pragma vector=USART1TX_VECTOR
__interrupt void SPI1_tx (void)
{
  unsigned int i;

  i = P1IN;
  i = i >> 4;
  TXBUF1 = i;                               // Transmit character
}